Without limit; indefinitely into the future; endlessly; describing something which goes on forever.

Jonathan Swift, an English satirist born in Ireland (1667-1745), wrote: "So, naturalists observe, a flea hath smaller fleas that on him prey; and these have smaller still to bite ‘em; and so proceed ad infinitum."

The term is often used interchangeably with ad nauseam and the original Latin sense is "beyond limits".